Molecular mechanism for conformation mobility of the active center of glucose oxidase adsorbed on single wall carbon nanotubes

Abstract

A critical issue in bioelectrochemical applications, that use electrodes modified by nanomaterials, like enzyme sensor modified by Single Wall Carbon Nanotubes (SWCNTs), is to ensure high activity of the active center of an immobilized enzyme protein. Since Flavin Adenine Dinucleotide (FAD) along with other amino residues, including His559, Glu412 and His516, constitute the active center of the catalytic site conformation of which could determine the activity of enzyme, it is important to understand the molecular mechanism of their mobility and the potential impact on the catalytic activity while GOx is immobilized on SWCNTs. However, this dynamic mechanism still remains blurry at the atomic level due to the active center being embedded in the apo-GOx and the limitations of appropriate experimental methods. The molecular dynamics (MD) simulation, as a successful approach for exploring some interaction details between protein and nanomaterials, was performed to investigate the mobility mechanism of the active center and the consequence for the possible change of catalytic activity in this study. The trajectory and bond distance clearly indicate that the adsorption of GOx onto SWCNTs with different orientations bring observable different interaction properties in the conformational mobility in active center. These results would help us understand some substantial factors for the activity of biomacromolecule while immobilized on nanomaterials.